==================================================================
BUG: KASAN: use-after-free in rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
Read of size 8 at addr ffff88813906fd90 by task udevd/388
CPU: 1 PID: 388 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x71/0x200 mm/kasan/report.c:316
print_report+0x4a/0x60 mm/kasan/report.c:420
kasan_report+0x122/0x150 mm/kasan/report.c:524
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351
rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
rcu_do_batch+0x4bc/0xc30 kernel/rcu/tree.c:2285
rcu_core+0x486/0xf00 kernel/rcu/tree.c:2557
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2574
handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:raw_read_seqcount_latch_retry include/linux/seqlock.h:713 [inline]
RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:209 [inline]
RIP: 0010:bpf_ksym_find kernel/bpf/core.c:689 [inline]
RIP: 0010:is_bpf_text_address+0x13c/0x190 kernel/bpf/core.c:723
Code: f6 74 0a e8 c6 77 f1 ff e9 4d ff ff ff e8 bc 77 f1 ff 45 31 e4 eb 0f e8 b2 77 f1 ff 45 31 e4 eb 09 e8 a8 77 f1 ff 4c 8b 6d d0 <8b> 05 7e dd 80 05 44 39 e8 74 14 e8 94 77 f1 ff 49 bc 00 00 00 00
RSP: 0018:ffffc9000dc4f660 EFLAGS: 00000246
RAX: ffffffff817fdd64 RBX: 0000000000000000 RCX: ffff888115526540
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa00041c0
RBP: ffffc9000dc4f690 R08: ffffc9000dc4f7d0 R09: ffffc9000dc4f7c8
R10: 000000000000000d R11: fffff52001b89eed R12: 0000000000000000
R13: 0000000000000062 R14: 0000000000000000 R15: ffffffffa00041c0
kernel_text_address+0xa0/0xd0 kernel/extable.c:125
__kernel_text_address+0xd/0x30 kernel/extable.c:79
unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_frame.c:19
arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
__call_rcu_common kernel/rcu/tree.c:2807 [inline]
call_rcu+0xcf/0xf50 kernel/rcu/tree.c:2926
security_inode_free+0xc5/0xe0 security/security.c:1073
__destroy_inode+0x175/0x500 fs/inode.c:289
destroy_inode fs/inode.c:312 [inline]
evict+0x777/0x8c0 fs/inode.c:724
iput_final fs/inode.c:1845 [inline]
iput+0x633/0x690 fs/inode.c:1871
d_delete_notify include/linux/fsnotify.h:292 [inline]
vfs_rmdir+0x3ad/0x4f0 fs/namei.c:4211
do_rmdir+0x261/0x6b0 fs/namei.c:4259
__do_sys_rmdir fs/namei.c:4278 [inline]
__se_sys_rmdir fs/namei.c:4276 [inline]
__x64_sys_rmdir+0x49/0x50 fs/namei.c:4276
x64_sys_call+0x68e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:85
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1801115407
Code: f0 ff ff 73 01 c3 48 8b 0d ee b9 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 54 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 c1 b9 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffc7b36f7c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007ffc7b36f7f0 RCX: 00007f1801115407
RDX: 0000000000000000 RSI: 00000000000007ce RDI: 00007ffc7b36fbf0
RBP: 000055d2a21de890 R08: 000055d2a21d4130 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000055d2a21dd4c0
R13: 00007ffc7b3703f0 R14: 0000000000000000 R15: 00007ffc7b36fbf0
Allocated by task 820:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:380 [inline]
__kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
kasan_kmalloc include/linux/kasan.h:212 [inline]
__do_kmalloc_node mm/slab_common.c:938 [inline]
__kmalloc+0xb4/0x1e0 mm/slab_common.c:951
kmalloc include/linux/slab.h:568 [inline]
kzalloc include/linux/slab.h:699 [inline]
l2tp_session_create+0x38/0xbd0 net/l2tp/l2tp_core.c:1609
pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:771
__sys_connect_file net/socket.c:2000 [inline]
__sys_connect+0x3da/0x460 net/socket.c:2017
__do_sys_connect net/socket.c:2027 [inline]
__se_sys_connect net/socket.c:2024 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2024
x64_sys_call+0x88d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 462:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
kasan_slab_free include/linux/kasan.h:178 [inline]
slab_free_hook mm/slub.c:1750 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
slab_free mm/slub.c:3712 [inline]
__kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
kfree+0x6f/0xf0 mm/slab_common.c:990
l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193
l2tp_session_delete+0x3df/0x4d0 net/l2tp/l2tp_core.c:1582
l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1228 [inline]
l2tp_tunnel_del_work+0x199/0x410 net/l2tp/l2tp_core.c:1266
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
__call_rcu_common kernel/rcu/tree.c:2807 [inline]
call_rcu+0xcf/0xf50 kernel/rcu/tree.c:2926
pppol2tp_release+0x1e3/0x2b0 net/l2tp/l2tp_ppp.c:446
__sock_release net/socket.c:652 [inline]
sock_close+0xc9/0x220 net/socket.c:1389
__fput+0x1fd/0x8f0 fs/file_table.c:320
____fput+0x15/0x20 fs/file_table.c:348
task_work_run+0x1e1/0x250 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff88813906fc00
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 400 bytes inside of
512-byte region [ffff88813906fc00, ffff88813906fe00)
The buggy address belongs to the physical page:
page:ffffea0004e41b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88813906f800 pfn:0x13906c
head:ffffea0004e41b00 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea0004e43a08 ffffea00044bf608 ffff888100042f00
raw: ffff88813906f800 000000000010000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 374, tgid 374 (kworker/u4:5), ts 28434341889, free_ts 27674658089
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
__alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
allocate_slab mm/slub.c:1967 [inline]
new_slab+0x98/0x3e0 mm/slub.c:2020
___slab_alloc+0x70f/0xb70 mm/slub.c:3177
__slab_alloc+0x5e/0xa0 mm/slub.c:3263
slab_alloc_node mm/slub.c:3348 [inline]
__kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
__do_kmalloc_node mm/slab_common.c:937 [inline]
__kmalloc_node_track_caller+0xa1/0x1e0 mm/slab_common.c:958
kmalloc_reserve net/core/skbuff.c:449 [inline]
__alloc_skb+0x226/0x4a0 net/core/skbuff.c:518
alloc_skb include/linux/skbuff.h:1322 [inline]
nlmsg_new include/net/netlink.h:987 [inline]
inet_netconf_notify_devconf+0x169/0x220 net/ipv4/devinet.c:2128
__devinet_sysctl_unregister net/ipv4/devinet.c:2639 [inline]
devinet_sysctl_unregister net/ipv4/devinet.c:2663 [inline]
inetdev_destroy net/ipv4/devinet.c:329 [inline]
inetdev_event+0x80a/0x10a0 net/ipv4/devinet.c:1615
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xa1/0x110 kernel/notifier.c:455
call_netdevice_notifiers_info net/core/dev.c:2022 [inline]
call_netdevice_notifiers_extack net/core/dev.c:2060 [inline]
call_netdevice_notifiers net/core/dev.c:2074 [inline]
unregister_netdevice_many+0x104a/0x1910 net/core/dev.c:11005
vti6_exit_batch_net+0x273/0x2c0 net/ipv6/ip6_vti.c:1191
page last free stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
free_pages_prepare mm/page_alloc.c:1580 [inline]
free_pcp_prepare mm/page_alloc.c:1654 [inline]
free_unref_page_prepare+0x80c/0x820 mm/page_alloc.c:3621
free_unref_page+0x93/0x530 mm/page_alloc.c:3719
free_the_page mm/page_alloc.c:863 [inline]
free_compound_page+0x99/0xd0 mm/page_alloc.c:886
destroy_large_folio+0x68/0xa0 mm/page_alloc.c:923
__folio_put_large mm/swap.c:113 [inline]
__folio_put+0xd1/0xe0 mm/swap.c:121
folio_put include/linux/mm.h:1442 [inline]
put_page include/linux/mm.h:1494 [inline]
io_pages_unmap+0x249/0x3a0 io_uring/io_uring.c:2521
io_rings_free+0x8f/0xe0 io_uring/io_uring.c:2533
io_ring_ctx_free+0x76b/0x987 io_uring/io_uring.c:2762
io_ring_exit_work+0x6cd/0x724 io_uring/io_uring.c:2936
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Memory state around the buggy address:
ffff88813906fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88813906fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88813906fd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88813906fe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88813906fe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 74 0a je 0xc
2: e8 c6 77 f1 ff call 0xfff177cd
7: e9 4d ff ff ff jmp 0xffffff59
c: e8 bc 77 f1 ff call 0xfff177cd
11: 45 31 e4 xor %r12d,%r12d
14: eb 0f jmp 0x25
16: e8 b2 77 f1 ff call 0xfff177cd
1b: 45 31 e4 xor %r12d,%r12d
1e: eb 09 jmp 0x29
20: e8 a8 77 f1 ff call 0xfff177cd
25: 4c 8b 6d d0 mov -0x30(%rbp),%r13
* 29: 8b 05 7e dd 80 05 mov 0x580dd7e(%rip),%eax # 0x580ddad <-- trapping instruction
2f: 44 39 e8 cmp %r13d,%eax
32: 74 14 je 0x48
34: e8 94 77 f1 ff call 0xfff177cd
39: 49 rex.WB
3a: bc 00 00 00 00 mov $0x0,%esp